B5c setup and gain question

I’m establishing a link between 2 sites, 24 miles. Design center says to use a 32dBi antenna. I’m using Ubiquiti’s 34dBi dish.

Link is established, and looks like I have everything dialed in. Signal meter showing PHY Tx/Rx at 1031 / 1299 which is outstanding (if it’s true). I haven’t done any type of throughput testing yet so we’ll see. In reading the docs, it’s saying to set the antenna gain to the type of dish. In my case, it’s defaulted at 10dBi, so I changed it to 34. In doing so, I start to see packet loss over the link, and the signal meter drops PHY Tx/Rx to 33 / 33. So I change it back to 10 and it seems a bit happier. I’m attaching some screenshots of the setup, I just want to make sure all is set properly before i continue on. In a few months, snow will fly again, and one side will not be accessible again except by snowmobile for a number of months.

Any guidance would be appreciated.




An add-on question I have is, on the signal meter, it says my target should be -98.5dBm, but when I even get close to that, I completely loose the other side, and they won’t connect. Is the target even applicable? Or am I just completely missing what should be done on setup?

Thanks.

Hello.

Probably you have make a mistake to set right GPS coordinate to permit radio to calculate right link length and target level. As target level, it’s impossible you should have -98. At 5 Ghz is not possible to make a link at -98.

Into the second image, the Tx EIRP and Tx Conducted is only 8/-2 dBm. It’s really strange values probably caused by DFS. Probably the radio detect some noises source and low down the power causing -84 as signal. You can try to change frequency.

I can suggest to use design tool to calculate the target signal and make a study before make the link just to compare with reality.

More I suggest to set the scheduler (TDMA traffic balance) always to auto.

More on first image you wrongly setup the antenna gain to 10 dB.

If you use Ubiquiti 34 dBi dish, there you need to set 34 dB gain on local and remote antenna too.

Coordinates are set by GPS, and LAT/LONG verified so they are correct. (new image)

2nd image (above) is when I change the Gain from 10 to 34 on both local and remote side antenna.

I did plan the link in the design center. That image also attached.

I changed, 1 at a time, the Center Freq 1 and Center Freq 2, that seemed to go well. I updated the design center with what I choose that looked clean.

I change gain back to 34, and waited a few minutes, and have signal lock again. Looks like the target changed to -48.5 dBm on the near and far side both. I ran a bandwidth test, the built-in one, and am getting 700ish MB up and 700MBish down. I’d be happy with that, but wondering what would I gain if I re-adjusted to try to come closer to the target of -48.5. I’d really like to get as much out of this link as possible, but not trying to be too greedy or sacrifice anything just for a little more throughput. How close to the actual Target is recommended? As close to or as spot on as possible?



Sincerly I use design tool and target signal only for my reference but it is almost impossible to reach value indicated there.

As you can see now the chosen channels are not DFS channels. This probably avoid problem of suddenly drop of signals and high noises. As if the radio would detect some radar or other interferences lowering tx power.

You need to look at noise on both channels (average and max for sure) and rx power. Compare always those values with modulation during the day. Probably it is better to look at value on cloud after some day of use to look at noise spike or drop of signal.

Anyway I have learned many of times a change of frequency is the key to solve problems.

At last, check always the signal and modulation behaviour during high load of traffic both in TX and RX sides.

Hi all,

Setting the antenna gain low (like 10 or 0) allows you to use much higher TX power than “legally” allowed. Setting the antenna gain at the correct value, in this case 34dBi, means your radio is then forced to transmit at legal EIRP levels. This is why your signal level and PHY rates drop. You aren’t transmitting at as high power anymore.

Your target value is incorrect because antenna gain isn’t set correctly. You should only expect this value if your antenna gain values are correct. You should use the design tool (design.mimosa.co) and create the link for a more accurate “target” value. You never want to aim for -98dBm. You always want to go for the strongest signal. So -60 is better than -90. -40 is better than -60.

For your reference, many WISPs do not conform to legal EIRP when using unlicensed channels. Is it right? Not at all. Do they do it anyway? They sure do. People only get in trouble when they are in DFS bands or licensed channels.

When you enter the high antenna gain the radio is bringing down the power to meet max EIRP regulation for your domain (USA )!! . if you are happy with the link just leave the gain at 10 . For your Long link you would need all the power available. If you are in the USA you need to worry about the regulatory issue. Rest of the world is tolerant unless you cause disruption to some one else. !!

I want to chime in here and say that the power “limits” are there for a reason!

When you are setting it up - using a higher power may be a good way to get the aiming correct - but leaving your radios above the EIRP limit can cause other issues - namely noise - this is why there are limits in place. If you cause noise your other radios in the area will suffer - if other wireless transmitters in the area dont follow the rules - then you will see more noise and your equipment will suffer.

Just my 2 cents.

:slight_smile:

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